saf-xc888cm-8ffi5v Infineon Technologies Corporation, saf-xc888cm-8ffi5v Datasheet - Page 28

• Manufacturer Part Number: saf-xc888cm-8ffi5v
• Description: 8-bit Single-chip Microcontroller
• Manufacturer: Infineon Technologies Corporation

code or data. Therefore, even though the ROM device contains either a 24-Kbyte or 32-
Kbyte ROM, the maximum size of code that can be placed in the ROM is the given size
less four bytes.
3.2.1
The XC886/888 memory protection strategy includes:
•
•
3.2.1.1
As long as a valid password is available, all external access to the device, including the
Flash, will be blocked.
For additional security, the Flash hardware protection can be enabled to implement a
second layer of read-out protection, as well as to enable program and erase protection.
Flash hardware protection is available only for Flash devices and comes in two modes:
•
•
The selection of each protection mode and the restrictions imposed are summarized in
Table
Table 4
Flash Protection Without hardware
Hardware
Protection Mode
Activation
Selection
P-Flash
contents can be
read by
External access
to P-Flash
Data Sheet
Read-out protection: The user is able to protect the contents in the Flash (for Flash
devices) and ROM (for ROM devices) memory from being read
– Flash protection is enabled by programming a valid password (8-bit non-zero
– ROM protection is fixed with the ROM mask and is always enabled.
Flash program and erase protection: This feature is available only for Flash devices.
Mode 0: Only the P-Flash is protected; the D-Flash is unprotected
Mode 1: Both the P-Flash and D-Flash are protected
value) via BSL mode 6.
4.
Memory Protection Strategy
Flash Memory Protection
Flash Protection Modes
protection
-
Program a valid password via BSL mode 6
Bit 4 of password = 0 Bit 4 of password = 1
Read instructions in
any program memory
Not possible
With hardware protection
0
MSB of password = 0
Read instructions in
the P-Flash
Not possible
21
Functional Description
1
Bit 4 of password = 1
MSB of password = 1
Read instructions in
the P-Flash or D-
Flash
Not possible
XC886/888CLM
V1.1, 2009-01